The Aleutians Campaign: The Only US Territory to be Invaded in World War II

In June 1942, Japanese forces seized two islands in the Aleutians chain, part of Alaska. It was the first foreign occupation of American territory since the War of 1812, and the battles to retake the islands of Kiska and Attu were proportionately more deadly than the campaigns at Iwo Jima or Okinawa. Yet today, the Aleutians campaign is largely forgotten.

American troops land on Attu.

In June 1942, Japanese Admiral Isoroku Yamamoto, the architect of the Pearl Harbor attack, was planning an ambush that would wipe out the American aircraft carrier fleet at a stroke and would, he hoped, force the United States to seek a peace settlement with Japan. Yamamoto planned to attack the US bases in the Aleutian Islands with a force containing two small aircraft carriers, the Ryujo and Junyo. This would compel the US carriers to leave Hawaii to defend Alaska. Once the American carriers were at sea, Yamamoto would attack and seize the strategic island of Midway, forcing the American fleet to divert. As the two American carriers (Yamamoto did not know that the carrier Yorktown had survived the Battle of the Coral Sea and the Americans actually had three carriers) approached Midway, they would be ambushed and destroyed by the Japanese fleet and its four aircraft carriers. With the US Pacific fleet crippled, Washington would be forced to seek terms with Japan.

Unknown to the Japanese, however, the US had broken Japan’s naval codes and knew the whole plan, and set up a counter-ambush of their own. The US fleet was sent to lie in wait near Midway to attack the Japanese fleet as it approached. When the Japanese launched their attack on the Aleutians on June 3, therefore, it had already failed in its strategic purpose. The Japanese also did not know that the US had two new airbases in the Aleutians–one near the naval base at Dutch Harbor and another at Umnak Island. The US Navy had in addition dispatched Task Force 8, consisting of cruisers and destroyers, to defend the area. The Japanese Northern Fleet would be facing considerably more resistance than they expected.

On June 3, the Japanese opened the battle with air strikes on Dutch Harbor. More raids followed over the next few days. But on June 4, the Americans launched their counter-ambush on the Japanese fleet at Midway. Four Japanese carriers were sunk, and Japan’s naval strength was crippled. It was the turning point in the Pacific War.

Nevertheless, the Japanese decided to occupy a number of islands in the Aleutians and establish bases there. This would interdict American shipping from the Pacific Northwest, give staging areas for raids on the US West Coast, and block any American efforts to approach Japan from the north. On June 6, Japanese troops entered the unoccupied island of Kiska, followed by the island of Attu the next day. They immediately began constructing an airfield on Kiska.

For a time, the Japanese forces in Alaska were neglected by American planners, as other priorities (especially Guadalcanal) were more vital. Each side in the Aleutians launched a series of air raids on the other, hampered by the Arctic conditions and the continual bad weather.

Once the Solomon Islands were secured, however, American attention turned to the Aleutians. The first task was to prevent the Japanese from resupplying their Aleutian outposts, and in March 1943 the US Navy intercepted a Japanese supply convoy in the Battle of the Kommandorski Islands. The next step was to remove the Japanese troops from Kiska and Attu. On May 11, 15,000 US troops landed on Attu, where they faced 2,900 Japanese Army troops. It was the first amphibious island landing of the war. The Japanese troops fought tenaciously, and it wasn’t until May 31 that the island was secured. Nearly the entire Japanese garrison had fought to the death; only 29 had been taken prisoner. The US lost 549 killed and 1148 wounded, one of the highest casualty rates in the entire war.

After the bloody battle to retake Attu, the US prepared for another fight at Kiska, where 5,000 Japanese troops waited. By the end of July, however, the Japanese realized that their position was hopeless and, under cover of bad weather, withdrew all their troops. When 15,000 American soldiers landed on Kiska on August 15, they found the island empty.

Unknown to most at the time, the Aleutians campaign also produced an important American intelligence coup. During one of the raids on Dutch Harbor on June 4, a Zero fighter flown by Petty Officer Tadayoshi Koga was hit by antiaircraft machine-gun fire that severed an oil line. Koga was forced to make an emergency landing on the small nearby island of Akutan, but when he touched down on the boggy soil, his wheels became stuck, the plane flipped over onto its back, and Koga’s neck was broken, killing him instantly. A month later, American reconnaissance flights spotted the downed Zero and sent a team to recover it. It was the first intact Zero fighter to fall into American hands. The plane was taken back to San Diego, where it was carefully dissected, reassembled, and test-flown dozens of times, giving US pilots (particularly for the new F6F Hellcat) invaluable information on the Zero’s capabilities and weaknesses.

5 thoughts on “The Aleutians Campaign: The Only US Territory to be Invaded in World War II”

One has to wonder whether those islands were strategically important enough to justify the loss of life incurred in retaking them. Perhaps they could have simply ignored it and focused on defeating Japan?

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Welcome to Hidden History Blog.

I’m Lenny Flank, Editor for Red and Black Publishers, and I'm your host. At "Hidden History", we’ll look at forgotten stories from history, strange and little-known discoveries in science, and the history behind the exhibits in some of the most famous (and not-so-famous) museums in the world. So settle in, get comfortable, and enjoy some unusual, odd, forgotten and weird history.